Method and device for producing ethylamine and butylamine

ABSTRACT

A process for preparing ethylamines, butylamines and mixed ethyl/butylamines comprising the following steps: (i) Hydroamination of butadiene and ethylene by means of a monoalkylamine and/or a dialkylamine in which alkyl=ethyl and/or butyl in the presence of an alkali metal amide as catalyst, (ii) isomerization of the amines obtained in the hydroamination (i), if appropriate under the following conditions: (iia) prior fractionation into particular fractions and/or (iib) isomerization under hydrogenating conditions and/or (iic) isomerization in the presence of ammonia, (iii) fractionation of the resulting product mixture with isolation of the desired product amines and recycle of the amines suitable as starting material to step (i).

The present invention relates to a process for preparing ethylamines andbutylamines.

Ethylamines and butylamines serve as starting materials for thepreparation of surfactants, textile and flotation auxiliaries,bactericides, corrosion and foam inhibitors, additives forpharmaceuticals and also as antioxidants for fats and oils. These aminescan be prepared by hydrogenation of the corresponding nitriles or nitrocompounds, by reductive amination of appropriate aldehydes and ketonesand by amination of appropriate alcohols. In particular, they areprepared on an industrial scale by amination of the correspondingalcohol or the corresponding carbonyl compound over metal catalysts,which may be supported or unsupported, under hydrogenative conditions.

The use of aldehydes, ketones and nitriles and also of alcohols, i.e.ethanol and butanol in the present case, as starting materials for thepreparation of alkylamines is in principle uneconomical compared to theuse of the corresponding olefins, i.e. ethene and butene, because of theprice of the starting materials.

An alternative way of preparing the amines mentioned is the addition ofNH3 or amines onto olefins in the presence of acid catalysts, forexample zeolites, basic catalysts, for example metal amides, inparticular alkali metal and alkaline earth metal amides, amides oftransition group IV, alkali metal alkoxides or of transition metalcomplexes.

However, this hydroamination of olefins suffers from a series ofdifficulties which frequently stand in the way of industrialimplementation of the reaction. Examples are indicated below.

Thus, in the NaNH₂ or KNH₂ catalyzed addition of NH₃ onto olefins, as isdescribed, for example, in B. W. Howk et al., J. Am. Chem. Soc. 76(1954), 1899-1902 and R. D. Closson et al., U.S. Pat. No. 2,750,417, thespace-time yields of the desired alkylamines are very small even at hightemperatures and olefin pressures because of the low activity andsolubility of the metal amide. U.S. Pat. No. 4,336,162 and U.S. Pat. No.4,302,603 describe a starting point for solving this problem by changingto rubidium and cesium amides or using a eutectic of NaNH₂ and KNH₂. Inthe first case, industrial implementation is prohibited by the extremelyhigh catalyst price, while in the second case, the space-time yields ofthe desired alkylamines are always too small.

The hydroamination of olefins using secondary amines in the presence ofacid catalysts generally proceeds in poorer yields and with poorerselectivities than the corresponding hydroamination using ammonia orprimary amines.

It is an object of the present invention to provide a process by meansof which ethylamines and butylamines and also mixed ethyl/butylaminescan be prepared in one process and the desired amounts of ethylamine andbutylamine prepared can be controlled.

We have found that this object is achieved by a process for preparingethylamines, butylamines and mixed ethyl/butylamines, which comprisesthe following steps:

-   -   (i) Hydroamination of butadiene and ethylene by means of a        monoalkylamine and/or a dialkylamine in which alkyl=ethyl and/or        butyl in the presence of an alkali metal amide as catalyst,    -   (ii) isomerization of the amines obtained in the hydroamination        (i), if appropriate under the following conditions:        -   prior fractionation into particular fractions and/or        -   isomerization under hydrogenating conditions and/or        -   isomerization in the presence of ammonia,    -   (iii) fractionation of the resulting product mixture with        isolation of the desired product amines and recycle of the        amines suitable as starting material to step (i) and, if        desired, to step (ii).

The process of the present invention allows the preparation of ethyl-and butyl-substituted organic amines, in particular triethylamine andtributylamine, in a combined process whose net reaction comprises, in apreferred embodiment, the reaction of hydrogen, ammonia, ethylene andbutadiene to form the amines mentioned. As starting material for thefirst reaction step, preference is given to using diethylamine,dibutylamine and/or ethylbutylamine, where these latter amines can alsobe formed fresh in the course of the process of the present inventionand be recirculated to the reaction.

The patent applications DE 10 030 619.5 and DE 10 041 676.4 by thepresent applicant, which are not prior publications, describe a generalprocess for preparing amines by hydroamination of olefins. In thisprocess, an olefin is reacted

-   -   a) with a primary amine or with a secondary amine in the        presence of a metal monoalkylamide or metal dialkylamide as        catalyst or    -   b) with ammonia or a primary amine in the presence of a solid        inorganic acid as catalyst or    -   c) with ammonia, a primary amine or a secondary amine in the        presence of a transition metal complex as catalyst        in a first process step and the hydroamination product or        products obtained are reacted in a second process step at from        80 to 400° C. either in the presence of a transalkylation        catalyst or in the presence of hydrogen and a transalkylating        hydrogenation or dehydrogenation catalyst.

These applications do not disclose the use of ethylene and butadienetogether in one process for preparing the corresponding ethyl- andbutyl-containing amines.

The process of the present invention is described in more detail below.

In the first process step, butadiene and ethylene are reacted with amonoalkylamine and/or a dialkylamine in which alkyl=ethyl and/or butylunder hydroaminating conditions. The addition of butadiene onto theamine forms a butenyl-containing amine, while the addition of ethyleneforms an ethyl-containing amine.

The relative amounts of the olefins to be hydroaminated (partialpressures) and the type and amount of the amines enable the distributionof the products formed to be controlled.

When a dialkylamine is employed, it is possible to use an amine havingmixed substitution. For example, use of diethylamine as amine results information of diethylbutenylamine and triethylamine, use ofmonoethylamine results in formation of ethyldibutenylamine,diethylbutenylamine and triethylamine, use of dibutylamine results information of dibutylbutenylamine and ethyldibutylamine, use ofbutylamine results in formation of butyldibutenylamine,butyldiethylamine and butylbutenylethylamine. Furthermore, the use ofthe olefins in a deficiency relative to the amine used results in amixture which further comprises secondary and/or primary amines beingobtained after the hydroamination.

When the process of the present invention is to be used to prepareproduct mixtures comprising mainly ethylamine, in particulartriethylamine, a high proportion of ethylene and/or ethylamine ordiethylamine is used in the hydroamination reaction. If a highproportion of butylamines, mainly tributylamine, is to be obtained, ahigh proportion of butadiene and/or butylamine or dibutylamine is used.

The hydroamination of the present invention is generally carried out sothat the amine and the olefin which give the alkylamine which is to bepreferably prepared are used in excess over the other starting materialsor are even used exclusively. In this case, the amine can also be usedas sole starting amine.

Preferred amines which are used in the process of the present inventionare diethylamine, dibutylamine and butylethylamine, in particulardiethylamine. Preference is given to adding a distinct excess ofethylene.

In one embodiment of the present invention, the hydroaminations of theethylene and of the butadiene are not carried out in a single reactionstep, but instead in two successive steps. Here, the order of thehydroaminations is immaterial; thus, the reaction of the amine withbutadiene can be carried out first and the reaction with ethylene can becarried out subsequently, or vice versa. Carrying out the hydroaminationin two separate steps has the advantage that the desired amount ofproducts relative to one another can be controlled more readily than inthe case of a single-stage process in which this is possible virtuallyonly via the partial pressures of the two olefins.

The hydroamination of ethylene and butylene is carried out using amidesof the alkali metals as catalysts.

Amides which can be used here are salts of Li, Na, K, Rb or Cs,preferably of Li, Na or K, in particular of Na.

The amides which can be used according to the present invention arederived from primary or secondary amines. These amines can have anysuitable substituents. These substituents are generally selected fromthe group consisting of linear and branched, cyclic and acyclicaliphatic and olefinic hydrocarbons which may bear one or moresubstituents from the group consisting of phenyl, amino and alkoxygroups. The hydrocarbons mentioned are preferably aliphatic cyclic oracyclic hydrocarbons having from 1 to 12 carbon atoms. Examples ofamines which can be used for preparing the amide include methylamine,dimethylamine, ethylamine, diethylamine, N-propylamine,di-n-propylamine, i-propylamine, di-i-propylamine, butylamine anddibutylamine. Amines and amides having mixed substituents can also beused.

It is also possible to use cyclic amines, for example pyrrolidine,piperidine, piperazine or morpholine, for preparing the amide.

Preference is given to using secondary aliphatic amines for preparingthe amide catalyst, with examples being dimethylamine, diethylamine,di-i-propylamine, di-n-propylamine, di-n-butylamine, di-i-butylamine anddi-sec-butylamine.

Even greater preference is given to using secondary amides which arederived from amines which are reacted with ethylene and/or butadiene inthe hydroamination reaction carried out according to the presentinvention.

Even greater preference still is given to using diethylamide,dibutylamide and/or ethylbutylamide as amide. In particular,diethylamide is used.

The metal amides can be used as such, for instance in the form of asolution, in the reaction according to the present invention, with themetal amides being able to come from any source.

In a preferred embodiment of the present invention, the metal amide is,prior to use in the reaction, prepared from the corresponding aminewhich is also reacted with the olefin, preferably diethylamine,dibutylamine and/or ethylbutylamine, in particular diethylamine. Thepreparation of the metal amides is carried out by methods known from theliterature. These are described, for example, in Houben-Weyl Methodender organischen Chemie, 4^(th) edition, Volume XI/2, Thieme Verlag,Stuttgart, pages 182 ff, U.S. Pat. No. 4,595,779, WO-A 93/14061, DE-A 2117 970 Deutsches Reichspatent 615,468, GB-A 742 790, DE-A 26 13 113,U.S. Pat. No. 2,750,417, J. Wollensak, Org. Synth. 43 (1963), pages 45ff and C. A. Brown, J. Am. Chem. Soc. 95 (1973), pages 982 ff. Ingeneral, the preparation of the amide comprises reacting a metal withthe corresponding amine in the presence of an unsaturated compound, forexample butadiene, isoprene, naphthalene, pyridine or styrene aselectron transferrer, reacting a metal amide or hydride with thecorresponding amine or reacting an organometallic compound, for examplen-BuLi, MeLi, PhNa, Et₂Mg or Et₄Zr, with the corresponding amine.

The above-described catalyst systems which are suitable for carrying outthe reaction of the present invention can be used in solution, as asuspension or in supported form.

If the metal amide is, as described, prepared prior to use in thereaction, this is preferably achieved by reacting the correspondingamine with the corresponding metal, which in the most preferredembodiment is Na. For this purpose, the Na is generally dispersed in thecorresponding amine, but it can also be dispersed in an inert solvent,for example a petroleum fraction, before addition of the amine. Afurther possibility is to disperse the alkali metal in the product amineor amines and to add the appropriate amine. If desired, a separateapparatus is used for the dispersion procedure, for example a stirredvessel, a nozzle or a reaction mixing pump. The reaction to form theamide salt proceeds in the presence of a suitable unsaturated compound,for example butadiene, isoprene, naphthalene, pyridine or styrene. In aparticularly preferred embodiment of the present invention, butadiene isused as unsaturated compound. This has the advantage that, owing to thepresence of butadiene which is hydroaminated according to the presentinvention by reaction with the amine, no additional unsaturated compoundhas to be added in the preparation of the amide.

In the preparation of the amide using sodium, the latter is generallyplaced in the reaction vessel in the form of fine particles. Theparticles preferably have a size distribution such that 50% by weight ofthe particles have a size of <1000 μm, more preferably <300 μm, inparticular <100 μm.

In the preparation of the amide catalyst from the elemental metal,preferably Na, a temperature of from 0 to 150° C., preferably from 20 to90° C., in particular from 30 to 70° C., and a pressure of from 1 to 200bar, preferably from 1 to 100 bar, in particular from 3 to 50 bar, areemployed. The preparation of the amide can be carried out batchwise,semicontinuously or continuously.

After the catalyst has been made available, butadiene and ethylene arereacted with the respective amine. This gives a mixture of amines havingethyl, butyl and/or butenyl substituents.

The relative amount of the organic amines formed can be controlled viathe amount of starting materials. After the hydroamination is complete,the mixture of the organic amines is fractionated as described below.

As regards the way in which the hydroamination reaction is carried out,there are a number of variants. For example the hydroamination ofbutadiene can be carried out first, followed by the hydroamination ofethylene. However, it is also possible to carry out both hydroaminationreactions in one reaction zone as a single-vessel synthesis. Thehydroamination reaction can in each case also be coupled with thepreparation of the catalyst.

In the hydroamination reactions, it is also possible for inertalkylamines such as triethylamine, tributylamine, butyldiethylamine anddibutylethylamine or saturated hydrocarbons to be present in thereactor.

In a preferred embodiment of the present invention, the preparation ofthe amide and the hydroamination of the butadiene are carried out in asingle process step. The hydroamination of the ethylene is carried outsubsequent thereto.

In this embodiment, it is advantageous to react butadiene firstly withthe amine to be alkylated, preferably diethylamine, dibutylamine and/orbutylethylamine, in particular diethylamine, in the presence of theamount of Na required to form the necessary amount of amide. Thepresence of butadiene results in the formation of the amide occurringspontaneously. A further electron transferrer can also be added, butthis is not preferred. The excess of the amine which is not reacted withthe Na to form the amide reacts with the butadiene to formbutene-containing amines. These are, for example, butenyldiethylamine,butenyldibutylamine and/or butenylbutylethylamine. The hydroamination ofbutadiene according to the present invention forms mainly linear butenylradicals in which the olefinic double bond is generally in the γposition relative to the N atom. However, double bond isomerization canalso result in the double bond being located in the α, β or δ positionrelative to the N atom. Branched butenyl radicals are generally notformed or formed only in minor amounts.

The amount of Na used in the preparation of the amide is chosen so thatthe molar ratio of Na to the total amount of olefin (butadiene plusethylene) is from 1:5 to 1:300, preferably from 1:10 to 1:200, inparticular from 1:50 to 1:150.

If the preparation of the amide and the hydroamination of butadiene arecarried out in combination as described above, this occurs at from 0 to150° C., preferably from 20 to 90° C., in particular from 30 to 70° C.,and at pressures of from 1 to 200 bar, preferably from 1 to 100 bar, inparticular from 3 to 50 bar.

In place of 1,3-butadiene, it is also possible to use1,3-butadiene-containing hydrocarbons, for example C₄ fractions as areobtained, for example, in the cracking of naphtha, in thedehydrogenation of LPG or LNG or in the Fischer-Tropsch synthesis.

Subsequent to the above-described butadiene hydroamination, theresulting reaction mixture is reacted with ethylene. In this step, notyet completely substituted amines are ethylated. This gives, forinstance in the case of the preferred use of dibutylamine,butylethylamine and/or diethylamine, the products dibutylethylamine,butyldiethylamine and/or triethylamine. If primary amines are used inthe preceding step of butadiene hydroamination, the reaction withethylene also forms amines which contain ethyl and butenyl substituents.Optionally, further diethylamine or monoethylamine can additionally beintroduced into the reactor, likewise inert trialkylamines.

The relative amounts of the various amines which are formed can beregulated via the type and amount of the starting materials, for examplethe amount of butadiene used in the butadiene hydroamination or theamount of further incompletely alkylated amine which is optionally addedafterwards.

In most cases, the main desired product will be triethylamine. In thiscase, an excess of ethylene over butadiene will be used. The excess ofethylene and, if appropriate, also the amount of amine, in particulardiethylamine, is preferably set so that triethylamine is formed in a5-20-fold excess over butyl-/butenyl-containing amines, in particular an8-12-fold excess.

The above-described hydroamination of ethylene is carried out at from 30to 180° C., preferably from 50 to 100° C., and at pressures of from 1 to200 bar, preferably from 20 to 200 bar, in particular from 30 to 50 bar.

In a further embodiment of the present invention, the hydroaminations ofbutadiene and of ethylene are carried out in a single reaction step. Inparticular, this reaction step also includes the preparation of theamide catalyst. In this case, the process is carried out at from 30 to180° C., preferably from 50 to 100° C., at pressures of from 1 to 200bar, preferably from 30 to 50 bar. However, the amide catalyst can alsobe prepared separately, but this is not preferred.

In all the above-described reaction variants, the reaction of the olefinwith the amine in the presence of the amide is carried out in a mannerknown to those skilled in the art. A description of preferred ways ofcarrying out the reaction may be found in G. P. Pez et al., Pure andApplied Chemistry 57 (1985), pages 1917 -26, R. D. Closson et al., J.Org. Chem. 22 (1957), pages 646 -9, U.S. Pat. No. 2,501,556, D.Steinborn et al., Z. Chem. 29 (1989), pages 333-4, D. Steinborn et al.,Z. Chem. 26 (1986), pages 349-59 and H. Lehmkuhl et al., J. Organomet.Chem. 55 (1973), pages 215-20. The reaction of the olefin with the aminein the presence of the metal alkylamide can also be carried out in thepresence of small amounts of ammonia, generally <1 mol % based on theamines used, as described, for example, in DE-A 21 17 970.

The metal alkylamide can, as described in DE-A-26 13 113, be transformedduring the reaction into a metal hydride by β-elimination or action ofH₂, forming an imine in the case of the β-elimination. This hydride canbe converted in the presence of a primary or secondary amine back intometal alkylamide and H₂ as described in DE-A 26 13 113, C. A. Brown, J.Am. Chem. Soc. 95(3) (1973), 982 ff or C. A. Brown, Synthesis (1978),754 ff, so that the metal hydride may be regarded as a type of “restform” of the metal alkylamide. It is therefore equivalent to the metalalkylamide for the purposes of the present invention.

Furthermore, complexing agents may be present as solvents both in thepreparation of the catalyst and in the reaction.

Thus, for example, J. F. Remenar (J. Am. Chem. Soc. 120 (1988), 4081ff), H. Lehmkuhl et al., (J. Organomet. Chem. 55 (1973), 215ff and D.Steinborn et al., (Z. Chem. 29 (1989), 333 ff, describe the use ofN,N,N′,N′-tetramethylethylenediamine,N,N,N′,N″,N″-pentamethyldiethylenetriamine,N,N,N′,N′-tetramethylcyclohexanediamine and tetrahydrofuran ascomplexing agents.

It is also possible to add amines having a plurality of amine nitrogenatoms per molecule, e.g. N,N,N′,N′-tetraethylethylenediamine,N-permethylated or N-perethylated triethylenetetramine through toN-permethylated or N-perethylated polyimine having molar masses up to500 000 dalton, ethers and polyethers such as diglyme, triglyme and thecorresponding homologues, end-capped polyols, e.g. PEG, PPG, polyTHF,and complexing agents containing amine nitrogen and ethyl oxygen atomsin the molecule, e.g. 3-methoxyethylamine,3-(2-methoxyethoxy)propylamine or bis(N,N′-dimethylaminoethyl)ether, tothe reaction mixture.

The catalyst can be present as a solution, as a suspension or insupported form on a typical catalyst support such as SiO₂, Al₂O₃, TiO₂,ZrO₂, activated carbon, MgO, MgAl₂O₄. The catalyst is preferably presentas a solution or suspension, particularly preferably as a solution.

The hydroamination of butadiene and/or ethylene can be carried outbatchwise, (addition of the olefin to the catalyst and amine),semicontinuously (addition of the olefin to the reaction mixture) orcontinuously (addition of all components).

In each case, preference is given to a molar ratio of olefin : secondaryamine of from 3:1 to 1:10, particularly preferably 1:1 to 1:2.

The ratio of olefin: primary amine is preferably from 6:1 to 1:5,particularly preferably from 2:1 to 1:1.

Possible reactors are all typical reaction apparatuses, e.g. stirredtanks, loop reactors, bubble columns, packed bubble columns, cascadedbubble columns and stirred columns.

Subsequent to the hydroamination reaction, the catalyst is separatedfrom the reaction mixture. This is carried out by customary methods, forexample distillation under reduced or atmospheric pressure, filtration,membrane filtration, sedimentation, washing with water, preferablyacids, salt solutions or alcohol.

Nonprotolyzed catalyst (metal alkylamide or metal hydride) cansubsequently be returned to the reaction.

Nonhydrolyzed catalyst is returned to the hydroamination reaction. It ispreferably recycled to the hydroamination of ethylene if this reactionis carried out as a separate step.

In one variant of the present invention, unreacted butadiene, ethyleneand any butenes formed are separated off together with the catalyst.

The next step of the process of the present invention is theisomerization, if appropriate under hydrogenating conditions and/or withaddition of NH_(3,) of the amines which have been obtained in thepreceding hydroamination reactions. This isomerization can precedefractionation of the amines. In any case, fractionation of the amines iscarried out after the isomerization. Part of the amines obtained afterisomerization/fractionation is then returned to the hydroaminationreaction with ethylene and/or butadiene. The type of isomerization andwhen it is carried out and how the reaction mixture formed in thehydroamination and the reaction mixture obtained after isomerization arefractionated depends on the desired product spectrum.

In the simplest case, the mixture obtained after the hydroamination ofthe amine with butadiene and ethylene, which comprises various butyl-,butenyl- and/or ethyl-substituted alkylamines, is subjected to anisomerization which, owing to the presence of butenyl groups in theamine, is carried out under hydrogenating conditions. A transalkylatinghydrogenation or dehydrogenation catalyst is used in this isomerization.In the isomerization, the product spectrum of the amines formed can beshifted to a larger proportion of one or more particular desiredamine(s). NH₃ can optionally be added. Addition of NH₃ effects theformation of secondary and/or primary amines which are preferably reusedas starting amines.

However, in a preferred embodiment of the present invention, aminescontaining butyl and/or butenyl groups can be separated off prior to theisomerization/hydrogenation. This fraction is subsequently hydrogenatedand isomerized with transalkylation. In a variant of this preferredembodiment, NH₃ is introduced in this isomerization/hydrogenation, sothat primary and secondary butyl-containing amines are also formed. Thisresults in butylamines which may, depending on the previous reactionconditions, contain one or two ethyl substituents when mixed ethyl- andbutyl-substituted amines (and not exclusively butyl-substituted amines)are used. The transalkylation is carried out using the conditions andcatalysts known to those skilled in the art. The desired products,preferably tributylamine, are generally separated off, either before orafter the transalkylation. The secondary and primary butyl-substitutedamines are then either recycled as starting materials or are once againtransalkylated under isomerizing conditions to form more tributylamine.

The mixture comprising triethylamine, diethylamine and possiblymonoethylamine which is obtained after the butyl-/butenyl-substitutedamines have been separated off is fractionated. This is preferablycarried out by distillation. This fractionation gives the desiredproduct, which is generally triethylamine. All or some of thetriethylamine is taken off from the process.

This fractionation also gives a mixture which is returned as startingmaterial to the hydroamination reaction, either directly or afterisomerizing transalkylation.

As mentioned above, a monoalkylamine or dialkylamine containing at leastone ethyl or butyl substituent is used as starting material in thehydroamination reaction. A secondary amine or a mixture of secondaryamines is preferably used as starting material. Preferred startingmaterials are diethylamine, dibutylamine or ethylbutylamine or a mixturecomprising one or more of these amines. In particular, diethylamine isused.

Depending on which amine or amines is/are to be recycled as startingmaterial to the hydroamination, the amine mixtures obtained after thecatalyst has been separated off are fractionated and, if appropriatewith addition of ammonia, transalkylated under isomerizing conditions.After the mixture has been fractionated again if necessary, part of theamines formed is recycled as starting material.

The transalkylation, which is carried out under conditions known tothose skilled in the art, thus provides starting amines for thehydroamination. The transalkylation step is generally carried out undera hydrogen atmosphere. Although such an atmosphere is not absolutelynecessary, it increases the activity and life of the catalyst used.

The transalkylation is carried out using conditions and catalysts knownto those skilled in the art. The composition of the starting mixture fedin depends, as mentioned above, on the amine to be used as startingmaterial for the hydroamination. Preference is given to usingtriethylamine, diethylamine as starting material for the transalkylationreaction. In particular, triethylamine and/or diethylamine are/is used.

The transalkylation reaction is preferably carried out with addition ofNH_(3,) which enables a high proportion of secondary amines in theproduct mixture from the transalkylation to be achieved.

The above-described transalkylation of the amines can in principle becarried out either with or without addition of NH₃. When NH₃ isexcluded, virtually no additional secondary and/or primary amines aregenerated. The amine mixture obtained in the hydroamination is in thiscase finally converted into tertiary amines, preferably triethylamineand tributylamine. The tertiary homosubstituted amines can easily beseparated from one another by distillation, i.e. generally triethylaminefrom tributylamine. The other amines are recirculated to form thedesired homosubstituted tertiary amines. In this way, the overall resultis to form the desired tertiary amines, preferably triethylamine andtributylamine, from the amines introduced into the hydroamination.

The isomerization/hydrogenation step can, if desired, be configured as areactive distillation. In this embodiment, too, depending on the desiredway in which the reaction is to be carried out, all amines obtainedafter the hydroamination may be present. The butenyl-/butyl-containingamines can also, if appropriate, have been separated off from the otheramines before one of the fractions obtained, if appropriate afterfurther prior fractionation, or else both fractions are subjected to theisomerization/transalkylation configured as a reactive distillation.

The above-described transalkylation reaction of the amines is carriedout at from 80 to 400° C.

In particular, the reaction of the hydroamination product undertransalkylating conditions can be carried out as described, for example,in Houben Weyl, Volume XI/1, nitrogen compounds II, 1957, Georg ThiemeVerlag Stuttgart, pp. 248 to 261.

Accordingly, the amine transalkylation (“amine exchange”) is carried outin the presence of dehydration catalysts andhydrogenation/dehydrogenation catalysts.

Dehydration catalysts suitable as transalkylation catalyst are, forexample, manganese(II) oxide/activated carbon, aluminum silicates,Al₂O₃, TiO₂ or ZrO₂.

To maintain the catalytic activity, the presence of hydrogen isadvantageous. Alternatively, the hydrogenation or dehydrogenationcatalyst can be freed of deposits by reduction with H₂ at regularintervals.

Catalysts suitable as hydrogenation and dehydrogenation catalysts areones which comprise, as catalytically active constituents, elements fromthe group consisting of copper, silver, gold, iron, cobalt, nickel,rhenium, ruthenium, rhodium, palladium, osmium, iridium, platinum,chromium, molybdenum and tungsten, in each case in metallic form(oxidation state 0) or in the form of compounds such as oxides which arereduced to the corresponding metal under the process conditions.

The catalytically active constituents copper, silver, gold, iron,cobalt, nickel, rhenium, ruthenium, rhodium, palladium, osmium, iridium,platinum, chromium, molybdenum and/or tungsten are generally present intotal amounts of from 0.1 to 80% by weight, preferably from 0.1 to 70%by weight, particularly preferably from 0.1 to 60% by weight, calculatedas metal in the oxidation state 0, in the catalytically activecomposition of the catalyst.

Preference is given to catalysts comprising, as catalytically activeconstituents, elements selected from the group consisting of copper,silver, cobalt, nickel, ruthenium, rhodium, palladium, platinum,chromium and molybdenum, in particular selected from the groupconsisting of copper, cobalt, nickel, in each case in metallic form(oxidation state 0) or in the form of compounds such as oxides which arereduced to the corresponding metal under the process conditions.

Greater preference is given to catalysts which comprise thecatalytically active constituents copper, silver, iron, cobalt, nickel,ruthenium, rhodium, palladium, osmium, iridium and/or platinum and asupport material preferably selected from the group consisting ofaluminum oxide, zirconium dioxide, titanium dioxide, carbon and/oroxygen-containing compounds of silicon.

The catalytically active composition of these catalysts which arepreferably used in the process of the present invention generallycomprises the catalytically active constituents copper, silver, iron,cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and/orplatinum in a total amount of from 0.1 to 80% by weight, preferably from0.1 to 70% by weight, particularly preferably from 0.1 to 60% by weight,calculated as metal in the oxidation state 0.

Furthermore, the catalytically active composition of these catalystswhich are preferably used generally comprises the support materialsaluminum oxide (Al₂O₃), zirconium dioxide (ZrO₂), titanium dioxide(TiO₂), carbon and/or oxygen-containing compounds of silicon, calculatedas SiO₂, in a total amount of from 20 to 99.9% by weight, preferablyfrom 30 to 99.9% by weight, particularly preferably from 40 to 99.9% byweight.

Particular preference is given to catalysts comprising the activecomponents Cu, Co, Ni and/or Pd, in particular Cu, Co and/or Ni. Thesecan be used as unsupported (all active) catalysts or as supportedcatalysts.

Very particular preference is given to Cu-containing catalysts which, asrecognized according to the present invention, are more selectivebecause of their comparatively low ethane or methane formation.

Examples are copper alloys, metallic copper, e.g. in the form of coppermesh, and Cu catalysts having a Cu content of from 2 to 70% by weight ofCu, calculated as CuO, on a support, preferably comprising from 10 to55% by weight of Cu, calculated as CuO, on a support. Preferred supportmaterials are aluminum oxide (Al₂O₃) zirconium dioxide (ZrO₂), titaniumdioxide (TiO₂), carbon and/or oxygen-containing compounds of silicon.

Examples of catalysts which can be used in the process of the presentinvention are those disclosed in EP-A 382 049, whose catalyticallyactive composition comprises, prior to treatment with hydrogen, from 20to 85% by weight, preferably from 70 to 80% by weight, of ZrO₂, from 1to 30% by weight, preferably from 1 to 10% by weight of CuO and from 1to 40% by weight each, preferably from 5 to 20% by weight each, of CuOand NiO, for example the catalysts described in loc. cit. on page 6which have the composition 76% by weight of Zr, calculated as ZrO₂, 4%by weight of Cu, calculated as CuO, 10% by weight of Co, calculated asCoO, and 10% by weight of Ni, calculated as NiO.

Furthermore, the catalysts disclosed in EP-A 963 875, whosecatalytically active composition prior to treatment with hydrogencomprises

-   -   from 22 to 40% by weight of ZrO₂,    -   from 1 to 30% by weight of oxygen-containing compounds of        copper, calculated as CuO,    -   from 15 to 50% by weight of oxygen-containing compounds of        nickel, calculated as NiO, with the molar Ni:Cu ratio being >1,    -   from 15 to 50% by weight of oxygen-containing compounds of        cobalt, calculated as CoO,    -   from 0 to 10% by weight of oxygen-containing compounds of        aluminum and/or manganese, calculated as Al₂O₃ and MnO₂,    -   and no oxygen-containing compounds of molybdenum, for example        the catalyst A disclosed in loc. cit., page 17, which has the        composition 33% by weight of Zr, calculated as ZrO₂, 28% by        weight of Ni, calculated as NiO, 11% by weight of Cu, calculated        as CuO, and 28% by weight of Co, calculated as CoO, can be used        in the process of the present invention.

In addition, the catalysts disclosed in EP-A 514 692, whosecatalytically active composition prior to treatment with hydrogencomprises from 5 to 100% by weight of an oxide of copper and nickel inan atomic ratio of from 1:1 to 10:1, preferably from 2:1 to 5:1, andzirconium oxide and/or aluminum oxide, in particular the catalystsdisclosed in loc. cit. on page 3, whose catalytically active compositionbefore treatment with hydrogen comprises from 20 to 80% by weight,particularly preferably from 40 to 70% by weight, of Al₂O₃ and/or ZrO₂,from 1 to 30% by weight of CuO, from 1 to 30% by weight of NiO and from1 to 30% by weight of CoO, can be used in the process of the presentinvention.

Preference is given to using the catalysts disclosed in the followingpatent applications:

Catalysts disclosed in DE-A 19 53 263 comprising cobalt, nickel andcopper and aluminum oxide and/or silicon dioxide and having a metalcontent of from 5 to 80% by weight, in particular from 10 to 30% byweight, based on the total catalyst, where the catalysts comprise,calculated on the basis of the metal content, from 70 to 95% by weightof a mixture of cobalt and nickel and from 5 to 30% by weight of copperand the weight ratio of cobalt to nickel is from 4:1 to 1:4, inparticular from 2:1 to 1:2;

-   -   catalysts disclosed in EP-A 696 572, whose catalytically active        composition prior to reduction with hydrogen comprises from 20        to 85% by weight of ZrO₂, from 1 to 30% by weight of        oxygen-containing compounds of copper, calculated as CuO, from        30 to 70% by weight of oxygen-containing compounds of nickel,        calculated as NiO, from 0.1 to 5% by weight of oxygen-containing        compounds of molybdenum, calculated as MoO₃, and from 0 to 10%        by weight of oxygen-containing compounds of aluminum and/or        manganese, calculated as Al₂O₃ and MnO₂, for example the        catalyst disclosed in loc. cit., page 8, which has the        composition 31.5% by weight of ZrO₂, 50% by weight of NiO, 17%        by weight of CuO and 1.5% by weight of MoO₃;    -   catalysts which are disclosed in EP-A 284 919 and have the        formula M_(x)Mg_(y)(SiO₂)*nH₂O, where M is a divalent, reducible        metal atom from the group consisting of Cu, Fe, Co and Ni, x and        y are numbers which together may reach the value 1.5 and n after        drying, expressed in % by weight, is from 0 to 80, for example        the catalyst described in loc. cit. in the example, which        comprises 35% of CuO, 9% of MgO and 38% of SiO₂, and the        catalyst which is described in EP-A 863 140 on page 3 and        comprises from 45 to 47% by weight of CuO, magnesium silicate        comprising about 15 to 17% by weight of MgO and from 35 to 36%        by weight of SiO₂, about 0.9% by weight of Cr₂O₃, about 1% by        weight of BaO and about 0.6% by weight of ZnO;    -   catalysts described in DE-A 24 45 303 which are obtainable by        heating a basic copper- and aluminum-containing carbonate of the        composition Cu_(m)Al₆(CO)_(0.5m)O₃(OH)_(m+12), where m is any,        not necessarily integral, value in the range from 2 to 6, at        from 350 to 700° C., for example the copper-containing        precipitated catalyst which is disclosed in loc. cit., Example        1, and is prepared by treatment of a solution of copper nitrate        and aluminum nitrate with sodium bicarbonate and subsequent        washing, drying and heat treatment of the precipitate; and    -   the supported catalysts which are disclosed in WO 95/32171 and        EP-A 816 350 and comprise from 5 to 50% by weight, preferably        from 15 to 40% by weight of copper, calculated as CuO, from 50        to 95% by weight, preferably from 60 to 85% by weight, of        silicon, calculated as SiO₂, from 0 to 20% by weight of        magnesium, calculated as MgO, from 0 to 5% by weight of barium,        calculated as BaO, from 0 to 5% by weight of zinc, calculated as        ZnO, and from 0 to 5% by weight of chromium, calculated as        Cr₂O₃, in each case based on the total weight of the calcined        catalyst, for example the catalyst which is disclosed in EP-A        816 350, page 5, and comprises 30% by weight of CuO and 70% by        weight of SiO₂.

The hydrogenation or dehydrogenation catalysts used as transalkylationcatalyst in the process of the present invention can be prepared by themethods described in the prior art, and some are also commerciallyavailable.

In the preparation of supported catalysts, there are no restrictions inrespect of the method by which the active components, e.g. nickel,cobalt and/or copper and possibly further components, are applied to thesupport material used.

In particular, the following application methods are useful:

-   -   a) impregnation        -   application of a metal salt solution to a prefabricated            inorganic support in one or more impregnation steps.            Subsequent to the impregnation, the support is dried and if            necessary calcined.    -   a1) The impregnation can be carried out by the “incipient        wetness” method, in which the support is moistened with an        amount of impregnation solution which is not more than the water        uptake capacity of the support. However, the impregnation can        also be carried out in an excess of solution.    -   a2) In multistage impregnation processes, it is advantageous to        dry and, if appropriate, calcine the material between individual        impregnation steps. Multistage impregnation is particularly        advantageous when the support is to be loaded with a relatively        large amount of metal.    -   a3) The inorganic support material is preferably used as        preshaped material in the impregnation, for example as powder,        spheres, extrudates or pellets. Particular preference is given        to using powder.    -   a4) As solvent for the metal salts, preference is given to using        concentrated aqueous ammonia.    -   a5) Promoters can be introduced in a step analogous to a1) by        impregnation with an appropriate metal-containing impregnation        solution, e.g. a copper-, cobalt- and/or nickel-containing        impregnation solution, and a promoter-containing impregnation        solution or in a plurality of stages, analogous to a2), by        alternate impregnation with metal-containing impregnation        solution and promoter-containing impregnation solution.    -   b) Precipitation        -   Precipitation of a metal salt solution onto a prefabricated,            inert inorganic support. In a particularly preferred            embodiment, this is present as powder in an aqueous            suspension.    -   b1) In one embodiment (i), precipitation is carried out using a        metal salt solution, preferably a sodium carbonate solution. As        substrate, use is made of an aqueous suspension of the support        material.    -   b2) In a further embodiment (ii), the precipitated catalyst can        be prepared in a two-stage process. Here, a powder is prepared        as described in a) and dried in a first stage. This powder is        converted into an aqueous suspension and used as substrate        equivalent to that described in embodiment (i).    -   b3) Promoters can be introduced in a step analogous to b1) by        precipitation of a metal-containing solution or in a plurality        of steps, analogous to b2), by successive precipitation of a        metal-containing solution and promoter-containing solution. In        the latter case, the individual precipitations can follow one        another directly or can be separated by a washing process and/or        drying process and/or calcination process.

As starting substances for a) and/or b), it is in principle possible touse all metal(I) and/or metal(II) salts which are soluble in thesolvents used in the application to the support, for example sulfates,nitrates, chlorides, carbonates, acetates, oxalates or ammoniumcomplexes. In a method as described in a), particular preference isgiven to using metal carbonates, while metal nitrates are particularlypreferably used for methods as described in b).

Solids resulting from a) or b) are filtered off in a customary mannerand are preferably washed free of alkali.

It is also possible to introduce a promoter component in a suitable forminto the filtered and, if appropriate, washed solid. Suitable forms are,for example, inorganic salts or complexes or organic compounds.

Both the end products from a) and those from b) are dried at from 50 to150° C., preferably from 100 to 140° C., and, if appropriate,subsequently heat treated, for example for a period of 2 hours, atelevated temperature, i.e. generally at from 200 to 400° C., inparticular from 200 to 220° C.

It is possible to introduce a promoter component in suitable form eitherafter drying or after heat treatment. Suitable forms are, for example,inorganic salts or complexes or organic compounds. Introduction isadvantageously carried out by intensive mixing, kneading and/orcompaction, with it being possible to add liquids such as water oralcohols if necessary. Introduction of the promoter component isadvantageously followed by a further drying and/or heat treatment step.However, if addition is carried out in the dry state, this may be ableto be omitted.

For use in the process of the present invention, the above-describeddried powder is preferably shaped to form tablets or similar shapedbodies. As tableting aid for the shaping process, graphite is added,preferably in a proportion of 3% by weight, based on the weight of thedried powder.

The tableted shaped bodies are preferably heated for 2 hours at from 300to 600° C., in particular from 330 to 350° C. This particular tabletingmethod allows, in contrast to the exclusive use of graphite as tabletingaid in customary methods, particularly easy shaping of the powder toform tablets and gives very chemically and mechanically stablecatalysts.

It is also possible to introduce a promoter component in a suitable forminto the shaped tablets. Suitable forms are, for example, solutions ofinorganic salts or complexes or organic compounds. Introduction isadvantageously followed by renewed drying at from 50 to 150° C.,preferably from 100 to 140° C. In addition, heat treatment can becarried out, preferably for about 2 hours at from 300 to 600° C., inparticular from 330 to 350° C.

If the reaction is carried out under transalkylating and simultaneouslyhydrogenating conditions, in particular in the presence of hydrogen anda transalkylating hydrogenation or dehydrogenation catalyst, preferredtransalkylating hydrogenation or dehydrogenation catalysts are the samehydrogenation and dehydrogenation catalysts as described above.

In a continuous transalkylation, the transalkylation catalyst isinstalled in a tube reactor or a shell-and-tube reactor. In the case ofa transalkylating dehydrogenation/hydrogenation reactor and operation inthe presence of H₂, the catalyst can, if desired, be reduced beforehandby means of hydrogen, but it can also be started up directly in thepresence of the product and hydrogen.

The hydrogen pressure can be in the range from 0 bar to 300 bar,preferably from 1 to 250 bar.

In the case of a reaction in the gas phase, the pressure is generallyfrom 1 to 70 bar.

In the case of a reaction in the liquid phase, the pressure is generallyfrom 70 to 250 bar.

The temperature is generally from 80 to 400° C., in particular from 100to 350° C., preferably from 120 to 250° C., very particularly preferablyfrom 150 to 250° C.

Depending on the temperature selected, an equilibrium of the alkylaminesplus any ammonia, which depends on the ratio of nitrogen to bulkinessand length of the alkyl groups is established. The bulkier the alkylgroups, the smaller the proportion of the corresponding tertiaryalkylamine.

The WHSV of the starting material over the catalyst can be from 0.05 to2 kg of starting material per liter of catalyst and per hour (kg/l*h),preferably from 0.1 to 1 kg/l*h, particularly preferably from 0.2 to 0.6kg/l*h.

The molar ratio of the amines obtained to one another can vary within awide range depending on the desired product mix.

After depressurization, the crude product can be distilled.

A preferred embodiment of the process of the present invention, in whichdiethylamine, dibutylamine and/or butylethylamine is/are used as amines,will now be illustrated by way of example with reference to FIG. 1.

In step (A1), the sodium amide corresponding to the secondary amine usedis prepared first. For this purpose, finely dispersed Na is reacted withthe amine in an inert solvent, the product amine or in the secondaryamine used, with addition of butadiene. The butadiene results in thereaction between the amine and Na taking place to form the amide andthus generate the catalyst species. Further butadiene and the secondaryamine then react to form a tertiary amine, namely butenyldiethylamine,butenyldibutylamine and/or butenylbutylethylamine. If only diethylamineis used as amine (preferred embodiment), butenyldiethylamine is formed.The process can be carried out batchwise, semicontinuously orcontinuously. The temperatures in the reaction are in the range from 0to 150° C., preferably from 20 to 90° C., in particular from 30 to 70°C., and the pressure is in the range from 1 to 200 bar, preferably from1 to 100 bar, in particular from 1 to 50 bar.

In process step (A2), the product mixture from step (A1) is then admixedwith ethylene, which results in any remaining amine having free H atomsbeing ethylated. The amount of free amine can be controlled via therelative amount of dialkylamine and butadiene which are reacted in step(A1). Depending on the starting amine, homosubstituted ormixed-substituted amines or mixture thereof are formed. Thus, in thecase of dibutylamine as starting material, ethyldibutylamine is formed,in the case of butylethylamine, butyldiethylamine is formed and in thecase of diethylamine, triethylamine is formed. Use of a mixture of twoor more of the starting materials mentioned makes it possible to obtaina mixture of various fully alkylated amines. Optionally, furtherdialkylamine starting material(s) or trialkylamine(s) can be added instep (A2) to control the product distribution.

Process step (A2) can be carried out batchwise, semicontinuously orcontinuously, and the temperature employed in the process is in therange from 30 to 180° C., preferably from 50 to 100° C., while thepressure is in the range from 1 to 200 bar, preferably from 20 to 100bar, in particular from 30 to 50 bar.

When using dialkylamine as starting material, the conversion can becontrolled so that it is up to 100%. However, preference is given tosetting the conversion to values of from 10 to 80%, in particular from30 to 70%.

Optionally, the reaction steps (A1) and (A2) can be combined into asingle reaction step (A). In this case, the proportion of butenylationsrelative to the ethylations is controlled via the concentration,generally the partial pressures, of the two olefins and via thetemperature.

After the hydroaminations described, the catalyst is separated off (notshown). This is generally achieved by customary separation methods, forexample (vacuum) distillation, membrane filtration, filtration,sedimentation or washing with protic reagents such as H₂O, aqueous saltsolutions or alcohols. Catalyst which is still intact can be returned tosteps (A1) and/or (A2). Unreacted butadiene and/or ethylene and anybutene formed can be separated off.

In step (B1), the product mixture is then separated intobutyl-/butenyl-containing amines and amines which do not contain butylor butenyl groups. Thus, butenyldiethylamine, butenyldibutylamine and/orbutenylbutylethylamine are separated from the other amines.

These amines are then hydrogenated and isomerized by means of hydrogenin step (C1) using a transalkylating hydrogenation or dehydrogenationcatalyst. The amines formed here are butyldiethylamine,dibutylethylamine, tributylamine and/or triethylamine. In general, themixed-substituted amines containing butyl and ethyl groups, whichnormally originate from the amine separation (B2), are fed to step (C1).The mixture obtained in (C1) is then passed to the abovementioned step(B2) for fractionation.

Step (B2), which follows step (B1), separates the amine mixture fromsteps (B1), (C1) and (C2). In this step, when diethylamine,butylethylamine and/or dibutylamine are used in the hydroaminationreaction, triethylamine, diethylbutylamine, tributylamine andethyldibutylamine and also the incompletely alkylated starting amineswhich, depending on the reaction conditions, may also have been formedin the reaction steps following the amine separation are separated fromone another.

In reaction step (C2), a product from the amine separation is isomerizedusing transalkylation and dehydrogenation/hydrogenation catalysts andwith addition of NH_(3,) generally under an H₂ atmosphere. In the mostpreferred embodiment of the present invention, in which diethylamine isused as amine in step (A1), triethylamine is taken from the amineseparation (B2). This is, if desired, taken as product from thesynthesis circuit, and, if desired, is at least partly isomerized instep (C2) to form a mixture which is rich in diethylamine. This mixtureis then recycled to the hydroamination reaction (A1) or (A2). In theother preferred embodiments in which dibutylamine and/or ethylbutylamineare/is used in step (A1) and/or (A2), the product taken from the amineseparation may also comprise tributylamine, dibutylamine andmixed-substituted amines which, for example, come from (C1). The productmixture obtained in (C2) is then fractionated, with the amines which areto be used as starting materials in the hydroamination reactions (A1)and/or (A2) being recycled to this step. Product amine is taken from thesystem. The other amines are returned to the amine separation.

The reaction is preferably carried out so that the net reaction, apartfrom the catalyst consumption which usually occurs, consumes onlyhydrogen, ammonia, ethylene and butadiene and gives a mixture comprisingmonoethylamine, diethylamine and triethylamine and monobutylamine,dibutylamine and tributylamine. The ratio of ethyl to butyl groups inthis mixture is in the range from 1:1000 to 1000:1. In general,monoalkylamines, dialkylamines and/or trialkylamines can also be added,in which case these amines are also consumed in the net reaction inaddition to the abovementioned components hydrogen, ammonia, ethyleneand butadiene. In any case, the process of the present invention iscarried out so that in the mass balance >50% of the nitrogen atomsoriginate from the ammonia, >50% of the ethyl groups originate fromethylene and >50% of the butyl groups originate from butadiene.

The reaction is illustrated by the following examples.

EXAMPLES Example 1 Sequential Addition of butadiene and ethylene ontodiethylamine

All work was carried out under argon; the organic starting materialswere dried over molecular sieves before use. The amination was carriedout in a 1 1 autoclave which had been dried under reduced pressure andflushed with argon before use.

60 mmol of Na were dispersed in 30 ml of n-dodecane at 120° C. by meansof an Ultraturrax, and the dispersion was then cooled without stirring(50% by weight of the particles were <60 um). In a sequence ofcentrifugation, decantation and addition of diethylamine, the dodecanewas then mostly replaced by diethylamine. Under a gentle stream ofargon, a dispersion of 60 mmol of sodium in 6 mol of diethylamine wasplaced in the reactor, the reactor was closed, heated to 50° C. and 131g of 1,3-butadiene as gas were dissolved in the dispersion over a periodof 4 hours while stirring. The introduction of butadiene was thenstopped, the contents of the autoclave were heated to 70° C. and theautoclave was pressurized with 40 bar of ethene. After the reaction wascomplete, the contents of the reactor were washed with 10 ml of 50%strength KOH solution in H₂O, the organic phase was separated off anddried. The composition of the reaction mixture determined by gaschromatography is shown in Table 1. TABLE 1 Hydroamination of butadieneand ethylene by diethylamine Species B1a B1b1 B1b2 B1b3 B1b4 B1c Timefrom addition of — 0.5 h 1 h 2 h 4 h 6 h ethylene Diethylamine 36.8526.34 22.39 19.18 15.17 15.67 Triethylamine —  5.14  9.58 14.60 20.2922.07 Butenyldiethylamine* 60.27 65.63 65.03 63.17 61.70 59.42*cis-1-, trans-1-, cis-2-, trans-2- and 3-butenyldiethylamine

Example 2 Sequential Addition of butadiene and ethylene ontodiethylamine and dibutylamine

The experiment was carried out as described in Example 1, but the Na wasdispersed directly in di-n-butylamine (50% by weight of the particleswere <150 μm). 1.5 mol of di-n-butylamine and 3 mol of diethylamine wereused as starting amines, and 81 g instead of 131 g of 1,3-butadiene wereadded. The composition of the reaction mixture determined by gaschromatography is reported in Table 2. TABLE 2 Hydroamination ofbutadiene and ethylene by diethylamine Species B2a B2b1 B2b2 B2b3 B2b4B2c Time from addition of — 0.5 h 1 h 2 h 4 h 6 h ethylene Diethylamine20.21 12.97 11.52 9.25 8.24 7.60 Triethylamine — 2.57 4.76 7.34 10.2811.45 Butenyldiethylamine* 32.74 32.84 32.33 31.78 31.27 30.83Dibutylamine 30.96 30.86 28.92 26.49 23.71 22.48 Ethyldibutylamine —2.09 3.93 6.58 9.03 10.21 Butenyldibutylamine* 13.16 15.69 15.44 15.4314.58 14.60*cis-1-, trans-1-, cis-2-, trans-2- and 3-butenyldiethylamine and -dibutylamine

Example 3 Simultaneous Addition of butadiene and ethylene ontodiethylamine and dibutylamine

The experiment was carried out as described in Example 2, but a mixtureof 2 mol % of butadiene and 98 mol % of ethylene was added at 40 bar and70° C. to the dispersion of Na and the amines. The composition of thereaction mixture determined by gas chromatography is reported in Table3. TABLE 3 Hydroamination of butadiene and ethylene by diethylamine(single-vessel reaction) Species B3b1 B3b2 B3b3 B3b4 B3c Time fromaddition of 0.5 h 1 h 2 h 4 h 6 h gas Diethylamine 35.63 28.84 22.6515.52 12.02 Triethylamine 3.01 5.54 8.02 10.91 12.19Butenyldiethylamine* 7.65 13.76 19.12 25.47 28.92 Dibutylamine 44.2736.64 30.39 23.57 21.36 Ethyldibutylamine 2.00 3.94 6.26 8.08 8.35Butenyldibutylamine* 3.44 6.60 10.61 14.20 15.15*cis-1-, trans-1-, cis-2-, trans-2- and 3-butenyldiethylamine and -dibutylamine

Example 4 Hydrogenative transalkylation of butenyldiethylamine

Diethylbutenylamine resulting from the addition of diethylamine ontobutadiene was, in pure form or as a mixture with triethylamine, passedcontinuously at 10 bar through a tube reactor. Two catalysts wereemployed:

-   -   Catalyst 1: 52% CuO, 10% NiO, balance Al₂O₃    -   Catalyst 2: 10% CoO, 10% NiO, 4% CuO, balance Al₂O₃    -   Both catalysts were heated to 280° C. under a hydrogen        atmosphere prior to the reaction.

At a pressure of 10 bar and 220° C., the starting materials were broughtinto the gas phase. The composition of the reaction mixture determinedby gas chromatography is reported in Table 4. TABLE 4 Transalkylation ofdiethylbutenylamine NH₃/ Temp Pressure Ammonia BDEA BDEA WHSV H₂ MEA DEACat. in ° C. in bar mol/h g/h mol/h ml/h Mol/mol kg/l*h [nl/h] RT = 3.37RT = 5.61 Starting Material: BDEA 1 220 10 0.2835 4.8 0.0945 15.8 3/l0-2 10 — 9.78 1 220 10 0.4725 8 0.0945 15.8 5/l 0.2 10 — 9.48 Startingmaterial: mixture of TEA + BDEA, 2:1 mol/mol 1 220 10 0.4725 8 15.8 5/l0.2 10 24.11 37.99 1 220 10 0.2835 4.8 15.8 3/l 0.2 10 15.06 36.66Starting Material: BDEA 2 190 10 0.0945 15.8 0.2 10 — 4.64 2 200 100.0945 15.8 0.2 10 — 6.52 2 210 10 0.0945 15.8 0.2 10  1.42 13.83 2 22010 0.0945 15.8 0.2 10  6.84 17.55 MBuA TEA EtBuA DEtBuA DBuA EtDBuA TBuACat. RT = 7.3 RT = 8.65 RT = 10.63 RT = 12.66 RT = 14.38 RT = 15.53 RT =17.78 Total 1 — 22.64 11.51 34.34 3.27 15.28 2.07 98.88 1 — 22.97 10.9334.57 3.06 15.01 2.05 98.06 1 4.56 12.99 12.37 5.55 1.11 0.96 — 99.64 13.11 19.79 13.68 9.17 1.20 1.32 — 99.99 2 — 11.88 6.65 64.43 1.49 9.621.28 99.98 2 — 14.84 9.13 52.75 2.49 12.35 1.84 99.92 2 1.14 17.36 16.3430.96 4.65 12.15 1.78 99.64 2 4.55  8.62 18.92 11.14 4.97 4.75 0.7278.06BDEA: butyldiethylamineMEA: monoethylamineDEA: diethylamineTEA: triethylamineEtBuA: ethylbutylamineDEtBuA: diethylbutylamineDBuA: dibutylamineEtDBuA ethyldibutylamineTBuA: tributylamine

Example 5 Hydrogenative transalkylation of the Reaction Mixture fromExample 2

The reaction product mixture from Example 2 was passed continuously at10 bar through a tube reactor. Catalyst 2 was used:

This was heated to 280° C. under a hydrogen atmosphere prior to thereaction. The mixture was hydrogenated at a pressure of 10 bar and 155°C. The reaction with ammonia was carried out at 210° C. The compositionof the reaction mixture determined by gas chromatography is reported inTable 5. TABLE 5 Transalkylation of the amine product mixture fromExample 2 NH₃/ BDEA BDEA Temp Pressure Ammonia ml/ mol/ WHSV H₂ MEA DEAMBuA in ° C. in bar mol/h g/h mol/h h mol kg/l*h [nl/h] RT = 3.37 RT =5.61 RT = 7.3 155  2 0.089 12 0.15 10 —  8.78  0.28 210 10 0.135 2.30.089 12 1.5/l 0.15 10  7.89 14.26  9.65 210 10 0.229 3.9 0.089 12 2.5/l0.15 10 10.02 14.75 11.79 210 10 0.447 7.6 0.089 12   5/l 0.15 10 16.9513.75 17.93 Temp TEA EtBuA DEtBuA DBuA EtDBuA TBuA in ° C. RT = 8.65 RT= 10.63 RT = 12.66 RT = 14.38 RT = 15.53 RT = 17.78 Total 155 12.49 4.99 23.02  8.39 13.46 28.58 99.99 210 4.9 27.31 11.44 12.91  9.14 2.49 99.99 210  4.26 26.83  9.19 13.01  7.47  2.67 99.99 210  2.6325.21  5.69 11.77  4.67  1.38 99.98BDEA: butyldiethylamineMEA: monoethylamineDEA: diethylamineTEA: triethylamineEtBuA: ethylbutylamineDEtBuA: diethylbutylamineDBuA: dibutylamineEtDBuA ethyldibutylamineTBuA: tributylamine

Example 6 Hydroyenative transalkylation of triethylamine

Triethylamine was passed continuously through a tube reactor. Twocatalysts were used:

The catalyst (52% CuO, 10% NiO, balance Al₂O₃) was heated to 280° C.under a hydrogen atmosphere prior to the reaction. The composition ofthe reaction mixture (in % by weight) is shown in Table 6. TABLE 6Transalkylation of triethylamine Feeds Temperature Triethylamine AmmoniaHydrogen Molar ratio WHSV in ° C. Pressure Analysis in ml/h g/h standardl/h Of NH₃/TEA in kg/l*h Preheater Oven in bar MEA DEA TEA 330 160 3003.9 0.40 200 200 50 19.64 51.93 28.43 330 160 300 3.9 0.40 180 180 5014.29 39.29 46.42 330 160 300 3.9 0.40 220 220 50 21.19 52.82 26.00 330160 300 3.9 0.40 170 170 50 12.39 35.04 52.57 330 160 300 3.9 0.40 180180 30 9.85 38.74 51.40 330 160 300 3.9 0.40 180 180 70 14.38 36.5649.06 490 240 300 4.0 0.60 180 180 50 13.71 36.92 49.37 490 240 300 4.00.60 200 200 50 19.44 50.96 29.60 490 240 300 4.0 0.60 220 220 50 21.4652.84 25.70 660 320 300 3.9 0.80 200 200 50 18.52 50.62 30.87 660 320300 3.9 0.80 220 220 50 21.75 52.75 25.50

1-14. (canceled)
 15. A process for preparing ethylamines, butylaminesand mixed ethyl/butylamines, which comprises the following steps: (i)hydroamination of butadiene and ethylene by means of a monoalkylamineand/or a dialkylamine in which alkyl=ethyl and/or butyl in the presenceof an alkali metal amide as catalyst, (ii) isomerization of the aminesobtained in the hydroamination (i), if appropriate under the followingconditions: (iia) prior fractionation into particular fractions and/or(iib) isomerization under hydrogenating conditions and/or (iic)isomerization in the presence of ammonia, (iii) fractionation of theresulting product mixture with isolation of the desired product aminesand recycle of the amines suitable as starting material to step (i) and,if desired, to step (ii).
 16. A process as claimed in claim 15, whereinthe hydroamination (i) is carried out so that the starting materialsnecessary for preparing the preferred product or products are added insuch amounts that the preferred product or products are formed inpredominant amounts.
 17. A process as claimed in claim 15, whereindiethylamine, dibutylamine or ethylbutylamine are used in thehydroamination reaction (i).
 18. A process as claimed in claim 15,wherein diethylamine is used in the hydroamination reaction.
 19. Aprocess as claimed in claim 15, wherein diethylamine and an excess ofethylene are used in the hydroamination reaction and the main productobtained is triethylamine.
 20. A process as claimed in claim 19, whereintriethylamine is obtained in a 5 to 20 fold excess, overbutyl-/butenyl-containing olefins.
 21. A process as claimed in claim 19,wherein triethylamine is obtained in a 8 to 12 fold excess, overbutyl-/butenyl-containing olefins.
 22. A process as claimed in claim 15,wherein the reaction mixture obtained in the hydroamination (i) isseparated in step (iia) into butenyl-containing amines and amines whichdo not contain butenyl groups and the fractions obtained are separatelyisomerized and/or hydrogenated.
 23. A process as claimed in claim 15,wherein the alkali metal amide is an amide of Na.
 24. A process asclaimed in claim 23, wherein the amide is from the group consisting ofdiethylamide, dibutylamide and ethylbutylamide.
 25. A process as claimedin claim 23, wherein the amide is diethylamide.
 26. A process as claimedin claim 23, wherein the metal amide is prepared from the amine which isreacted with the olefin in the hydroamination reaction.
 27. A process asclaimed in claim 26, wherein the metal amide is prepared from the amineby reaction with the corresponding alkali metal in the presence ofbutadiene.
 28. A process as claimed in claim 27, wherein the metal amideis prepared in situ in the hydroamination reaction (i).
 29. A process asclaimed in claim 15, wherein the starting amine or amines is/are reactedfirstly with butadiene and then with ethylene in the hydroamination (i).30. A process as claimed in claim 29, wherein the reactants are reactedin a single stage reaction.
 31. A process as claimed in claim 30,wherein the reactants are reacted in a single stage reaction withsimultaneous formation of the metal amide.
 32. A process as claimed inclaim 15, wherein amines containing butyl and/or butenyl groups areseparated off in step (iia) and are subsequently hydrogenated andisomerized with transalkylation in step (ii), in the presence or absenceof NH₃ to form primary and secondary butyl-containing amines.
 33. Aprocess as claimed in claim 15, wherein the mixture obtained after thebutyl-/butenyl-substituted amines have been separated off, whichcomprises triethylamine, diethylamine and possibly monoethylamine, isfractionated to give the desired product, and all or some of the desiredproduct is taken from the process and another mixture is separated offand is recycled either directly or after isomerizing transalkylation asstarting material to the hydroamination reaction.
 34. A process asclaimed in claim 33, wherein the desired product is triethylamine.
 35. Aprocess as claimed in claim 15, wherein the transalkylation is carriedout in the presence of dehydration catalysts andhydrogenation/dehydrogenation catalysts which comprise elements selectedfrom the group consisting of copper, silver, gold, iron, cobalt, nickel,rhenium, ruthenium, rhodium, palladium, osmium, iridium, platinum,chromium, molybdenum and tungsten either in metallic form or in the formof compounds which are reduced to the corresponding metal under theprocess conditions as catalytically active constituents.
 36. A processas claimed in claim 35, wherein the catalysts comprise a supportmaterial selected from the group consisting of aluminum oxide, zirconiumdioxide, titanium dioxide, carbon and/or silicon dioxide.
 37. A processas claimed in claim 15, where one or more of the transalkylationreaction are carried out in the presence of hydrogen or NH₃.
 38. Aprocess for preparing ethylamines and butylamines, wherein butadiene,ethylene, hydrogen, ammonia and monoalkylamine, dialkylamine and/ortrialkylamine in the alkyl=ethyl or butyl are reacted with one anotherin the presence of amide catalyst to give a mixture which comprisesmonoethylamine, diethylamine, triethylamine, monobutylamine,dibutylamine and tributylamine and in the ratio of the ethyl groups tothe butyl groups is in the range from 1:1000 to 1000:1 and in the massbalance>50% of the nitrogen atoms originate from the ammonia>50% of theethyl groups originate from ethylene and >50% of the butyl groupsoriginate from butadiene.
 39. A process as claimed in claim 38, whereinthe reaction is carried out so that in the net reaction only hydrogen,ammonia, ethylene and butadiene are consumed.